Improvement in reverberatory and other draft-furnaces



it p.

NITED STA'rns JOHN R. GROUT, OF DETROIT, MICHIGAN.

I IMPROVEMENT IN REVERBERAIORY AND OTHER DRAFT-FURNACES.

Specification forming'part of Letters Patent No. 56,552, dated July 24, 1866.

. Fig. 2, a vertical section in the bridge-wall transversely; Fig. 3, a vertical section of the bridge-wall face toward the melting-apartment; and Fig. 4, a vertical section of the arch over the fire-room and bridge-wall of a melting and refining reverberatory furnace, with the invention applied; Fig. 5, the parts which form the valve in the bridgewall passage-ways; Fig. 6, the parts which form thevalve in the arch passage-ways; and Fig. 7, a perspective view of the furnace in form with the lower part of the chimney.

The nature of my invention consists in ap plying the heat from the solid fuels in combustion on the grate of furnaces to the heating of atmospheric air, to be admitted in regulated currents to the gases from the solid fuels as they enter the heating or melting apartment of the furnace, where, receiving fresh air at a high heat, the full combustion of the gases takes place, producing alargeincrease of heat in the heating or melting apartment and protecting the metal in treatment from the effects of the gases unburned.

In applying my invention to furnaces for smelting native copper mineral, or for any purpose where intense heat and its ready adjustment or variation is required, I make my chimney with less power of draft, my bridgewall of more width, and fire-room of more depth and area on the grate than is usual, providing closing grateroom and fire 'or coolin g doors; and I construct passage-ways in the masonry which incloses the fire-room, which masonry is constantly held at a high red heat by the combustion of the solid fuels on the grate, and through these passage-ways I admit atmospheric air to the heating or melting apartment of the furnace, which air, in passing, is raised to the heat of the masonry with which it is in contact. ()ne passage-wayis in the bridge-wall and another in the arch or crown of the furnace over the fire-room and bridgewall, these airways entering the heating or melting apartment at the section connecting the latter with the bridge-wall.

A, B, G, D, and E, Fi 1, respectively, represent the grate, fire-room, passage over bridge-wall, heating and melting apartment, and flue connecting the chimney.

a a a represent the atmospheric passagewayin the bridge-wall, and I) b b its passageway in the arch of the furnace.

At a, I provide a valve for closing the passage-way in the bridgewall and for regulating the current of air. The valve rests upon the masonry, and, in connection with the passage-way bridge 0 upon the heavy plate (I, is tightly embedded at a point where the heat is steady, but not sufficient to melt it. Below the valve the passage-way is single, but above it is in several channels, as appears by Fig. 2, which is a section showing the heavy plate (I, the valve and passageway bridge 0 resting upon the plate, and four channels of the passageway over these, which channels are continued and, rapidly rising, enter the heating and melting apartment at a, as shown by Fig. 3, at or near the upper corner of the bridge-wall. At the entrance to the passage-way, beneath the grate, a plate, 0, fillin g the width of the grateway, is hinged tightly to plate (1, directing the entrance of the air between it and the grate. In like manner I provide a valve at b for closing the passage-way in the arch of the furnace and regulating the passing of the air through it. This passage-way is in two channels, as shown in Fig. 4, which below the valve extend horizontally in the arch over the fire-room and the bridge-wall, and then, declining rapidly, enter the heating and melting apartment at b directly over a.

The bridgeway-valve is shown in Fi 5, and is composed of a bottom plate, a sliding plate, a rod, and lever. The bottom plate, f, contains an opening through it for the passing of the air and a diagonal slot at each end, as shown. It is firmly set in masonry, as before described, at a. Sliding plate g, cast diagonal at each end, lies upon plate f, and is provided with two pins, one near each end, which fit into the slats in f. Rod h attaches to plate g at its center point, and connects it through a guiding-staple with lever i. Lever 1." stands in the angle on the outside of the furnace shown in Fig. 7, by means of which lever so connected with plate g the opening through f is closed fully or in any part by the sliding of plate 9 at pleasure. The lever is pro-v vided with an arc, showing at any time the space open and quantity of air passing.

The valve to the passage-ways in the arch is shown in Fig. 6, and is constructed as the bridgeway-valve, the same parts being indieated by the same letters with a dash, except that f is provided with double openings, and g is in two slide-plates, requiring a rod connecting them at centers, the center of which rod is connected by 71/ with i, which is on the outer corner of the furnace, Fig. 7 This valve is operated in same manner as the other. The grate-room is also provided with closing doors j, and also the fire-room, so as to lessen or stop entirely the consumption of the fuel when desired.

When the furnace is in work, a heavy body of coal or fuel is maintained on the grate, the fire or coaling dooris closed, except when replenishing the fire, which is at intervals of about one and a half hour, and no air is admitted to the coal except through the grate, and the rate of combustion of the solid fuels is regulated by the doors of the grate-room and the damper to the chimney or stack. The masonry of the bridge-wall facing the fire-room, and over the air passage-way in the wall, and at its connection above and below the air passageway with the heating and melting apartment is constantly at a high red heat, and the atmospheric air, in being drawn through the passageway, as the arrows indicate, by the draft of the furnace, is raised to a high degree of heat, in which state it enters sharply upward into the hot gases flowing over the bridge-wall into the heating and melting apartment, where it unites in combustion with them. In like manner the masonry of the arch over the fire-room and bridge-wall is constantly at a red heat, though less in degree than that of the bridge-wall, and the air, in its passage, as the arrows indicate, is raised to the same heat, at which heat it enters sharply downward into the hot gases and combines in like manner with them. It is in both cases admitted by the proper position of the valves in the relative proportion to combine with the gases, and, mixing with them in the same sectional plane of the furnace, they are carried forward by the action of the draft in the state of combustion through the whole body of the heating and melting apartment. Their free diffusion in combustion equalizes the heat in every part of the apartment, and their entire combustion neutralizes any effect of the gases injuriously on the metal in treatment.

The masonry of the fire-room, including the bridge-wall, and the arch over these, are the parts of the furnace that first receive heat.

When the requisite quantity of fuel on the grate is fully inflamed and this masonry is sufficiently hot, the atmospheric air allowed to pass the valves becomes heated to the point at which it combines in free combustion with the gases. a little at first, then more, and the draft adjusted to an active combustion of the fuels, when. the heat of the furnace is rapidly raised to its full execution. Both valves may be opened at the same time, admitting the requisite volume of air, or one only be open, admitting the same volume.

The bridge-wall valve is especially useful when desulphuration or the oxidation of impurities from the metal is required. Air admitted by it in excess, with a slight lessening of the draft, acts directly on the metal in treatment. This oxidizing effect is of value. At the same time by a readjustment of the valve and the draft it ceases. The same effect is not subject to be obtained from the valve in the arch.

At intervals when the furnace is not in work and retention of heat is desired the valves are closed, and the grate-doorsand the damper nearly. The combustion of the solid fuels falls then to the minimum, but subject to become active again by the opening of these parts.

The bridge 0, extending across the atmospheric passage-way a a a at a serves as a protection for the valve against molten materials flowing down the passage-way from a, and which would otherwise flow over and prevent the operation of the valve.

Having fully set forth the nature of my im- I provements, what I claim as my invention, and seek to secure by Letters Patent, is

1. In a reverberatin g or other draft-furnace, so arranging the atmospheric passage-ways a a a and b b b in the bridge-wall and arch of the furnace that the air passing in thin currents shall be heated by contact with the walls, and introduced from above and below into the compartment D in converging currents of the full width of the throat 0, where, mingling with the unconsumed carbonized gases evolved from the fuel in the fire-room B, their complete combustion and perfect diffusion will be effected, substantially in the manner set forth.

2. The combination of the plate f, valve 9, rod h, and lever t in the lower air-passage, and thesimilar combination in the upper airpassage, or their equivalents, for the regulation of the passage of air through the atmospheric passage-ways a and 12, substantially as and for the purposes set forth.

3. Constructing the bridge cacross the lower atmospheric passage-way for the protection of the valve, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

Witnessesz' JOHN It. GROUT.

It. MASON, JOHN S. HOLLINGSHEAJ).

The valves are then opened I 

